To expand the representation for phylogenetic analysis, ten additional complete Entamoeba small-subunit rRNA gene sequences were obtained from humans, non-human primates, cattle and a tortoise. For... Show moreTo expand the representation for phylogenetic analysis, ten additional complete Entamoeba small-subunit rRNA gene sequences were obtained from humans, non-human primates, cattle and a tortoise. For some novel sequences no corresponding morphological data were available, and we suggest that these organisms should be referred to as ribosomal lineages (RL) rather than being assigned species names at present. To investigate genetic diversity and host specificity of selected Entamoeba species, a total of 91 new partial small subunit rRNA gene sequences were obtained, including 49 from Entamoeba coli, 18 from Entamoeba polecki, and 17 from Entamoeba hartmanni. We propose a new nomenclature for significant variants within established Entamoeba species. Based on current data we propose that the uninucleated-cyst-producing Entamoeba infecting humans is called Entamoeba polecki and divided into four subtypes (ST1-ST4) and that Entamoeba coli is divided into two subtypes (ST1-ST2). New hosts for several species were detected and, while host specificity and genetic diversity of several species remain to be clarified, it is clear that previous reliance on cultivated material has given us a misleading and incomplete picture of variation within the genus Entamoeba. (C) 2010 Elsevier GmbH. All rights reserved. Show less
Detection of intestinal parasitic protists, commonly referred to as 'intestinal protozoa,' by PCR is increasingly used not only for identification or confirmation but also as a first-line... Show moreDetection of intestinal parasitic protists, commonly referred to as 'intestinal protozoa,' by PCR is increasingly used not only for identification or confirmation but also as a first-line diagnostic tool. Apart from the ability to sample correctly and extract parasite DNA directly from faeces, primer and probe specificity and sensitivity affect predictive values and hence the utility of diagnostic assays. Molecular characterization of intestinal protists is necessary to design primers and probes because this is the basic material for current and future improved diagnostic PCRs for either detecting all genetic variants or specifically differentiating among such variants. As an example, this paper highlights the existence of interspecific and intraspecific genetic diversity among intestinal, unicellular parasites and its implications for nucleic acid-based diagnostic assays. Show less
Stensvold, C.R.; Lebbad, M.; Verweij, J.J.; Jespersgaard, C.; Samson-Himmelstjerna, G. von; Nielsen, S.S.; Nielsen, H.V. 2010
A method using a single-round PCR coupled to pyrosequencing was developed for the detection and differentiation of members of the Entamoeba complex The technique was evaluated using DNA Isolated... Show moreA method using a single-round PCR coupled to pyrosequencing was developed for the detection and differentiation of members of the Entamoeba complex The technique was evaluated using DNA Isolated directly from faecal specimens and compared with a duplex real-time PCR targeting Entamoeba histo lytica and Entamoeba dispar and a conventional single-round PCR for the detection of Entamoeba moshkovskii Tetranucleate cysts from 102 faecal specimens from Swedish Danish and Dutch patients test-positive for the Entamoeba complex by coproscopic examination were identified to species using each of the three methods Although none of the patients were confirmed to be positive for E moshkovskii E histolytica and E dispar were identified in 17 and 86 of the samples respectively one of the samples containing both species There was concordance in results between pyrosequencing and the two other methods used This study showed that PCR and pyrosequencing could be used for the rapid and high throughput identification of Entamoeba species (C) 2010 Elsevier Ltd All rights reserved Show less
